Naval Group and Centrale Nantes print the world’s first hollow propeller blade

Naval Group and Centrale Nantes have printed the first demonstrator of hollow propeller blades by metal additive manufacturing as part of the European H2020 project, RAMSSES. Funded by the European Commission, this collaborative programme aims to reduce the environmental impact of ships.

on February 7, 2019

In order to improve vessel propulsion, Centrale Nantes and Naval Group are using additive manufacturing to design large parts (propellers of 6 metres in diameter), which could not be produced thus far using traditional manufacturing technologies. Implementing the WAAM (Wire Arc for Additive Manufacturing) process, allows for the printing of large parts and paves the way for the production of propellers with more complex geometry.

Substantial industrial and operational gains

The one-third scale hollow blade demonstrator, representative of a container ship propeller, was printed in stainless steel in under one hundred hours, weighing in at about 300kg. The teams’ sheer technical prowess means that weight gains of over 40% will be achievable compared to conventional processes.

Sirehna, a Centrale Nantes spin-off and subsidiary of Naval Group, is piloting the blade design in order to improve propeller energy efficiency and reduce their environmental impact. Sirehna's work has led to an overall optimization of blades in terms of efficiency and endurance, but also a significant reduction in radiated noise

and vibrations.

Naval Group and Sirehna have been able to count on the exceptional technical resources and extensive knowledge offered by Centrale Nantes. The school’s expertise in trajectory generation and additive manufacturing is needed to produce the blade. This long-standing co-operation took on a formal footing in 2016 with the creation of the Joint Laboratory of Marine Technology.

Naval Group’s Patrice Vinot, Propeller Package Manager for the RAMSSES project, underlines the challenge of such a manufacturing process: Although additive manufacturing is increasingly present in industry, the programming and design of complex parts, such as propeller blades for ships, represents a considerable challenge for our teams, and our partners. The potential of the process revealed by this new case study means that we now anticipate unparalleled performance for the propellers of tomorrow. Taking part in projects such as RAMSSES and coordinating our network of academic and industrial partners, will allow us to bring 3D printing into shipyards for the long term.

Professor Jean-Yves Hascoët, head of the Rapid Manufacturing Platform at Centrale Nantes and international expert in additive manufacturing: Additive manufacturing has been developed over the last 35 years on the Rapid Manufacturing Platform. All these years of research come to fruition through a project like RAMSSES, which represents a real transfer of our technologies into an industrial environment.